Full details of the new measures are to be released today. But a statement made clear they would include the creation of a new compliance authority and the introduction of legislation to combat money laundering and the financing of terrorism.

The Vatican bank, known as the Institute for the Works of Religion, or IOR, is perhaps the world's most extraordinary financial organisation. Its reputedly state-of-the-art facilities are housed in a 15th century tower next to the pope's palace and its ATM behind St Peter's Basilica is in Latin (a cash withdrawal being "deductio ex pecunia").

In the 1980s the IOR was at the centre of a long-running scandal arising from its involvement in the $1.3bn collapse of Italy's largest private bank, Banco Ambrosiano, and the death of the bank's chairman, Roberto Calvi, whose body was found hanging under Blackfriars Bridge in London. The Vatican denied any wrongdoing but paid $250m to Ambrosiano's creditors. More recently, in October, police in Sicily said they had uncovered a money-laundering operation that involved the use of an IOR account opened by a priest with family connections to the Mafia.

The IOR was set up to look after the wealth of Catholic organisations, such as religious orders. Its statutes allow lay individuals to open accounts, but only if the purpose is to promote "works of religion or charity".

The new rules appeared designed to comply with a mutually agreed deadline of 31 December for the implementation of the EU's money-laundering directive. The Vatican had also undertaken to set up a financial watchdog body by the first day of 2011.

The Holy See's lawyers have twice tried, without success, to get the Italian courts to free the assets seized three months ago. The Vatican, which appointed Gotti Tedeschi to impose greater transparency on the IOR and ensure it complied with international anti-money laundering regulations, has insisted the affair is the result of a misunderstanding and that it was merely trying to move its own cash around. But earlier this month an Italian judge criticised the Vatican bank for continuing to hide the identity of its clients.